Jīn Zǐjiǔ 金子久 (míng Bǎozhī 保之, zì Zǐjiǔ, hào Císhēng 慈生, 1870–1921) was the leading Húzhōu 湖州 physician of the late-Qīng-early-Republican transition, native of Tóngxiāng 桐鄉 (Zhèjiāng). He studied first under his uncle Jīn Yuèzhī 金嶽芝 and then with Hé Xìngrán 何興然, eventually building a major practice with a reputation that drew patients from across the lower Yangtze. His clinical synthesis fused warm-disease (after Yè Tiānshì 葉桂) with the Mènghé style and his own emphasis on jiējǐng 接濟 (sustaining the patient’s yīn through severe illness). His outpatient case records — Jīnshì ménzhěn fāngàn 金氏門診方案 (KR3ed070) — preserve about a thousand cases from his Húzhōu clinic and remain a major source for late-Qīng/Republican lower-Yangtze clinical practice. He died of overwork in 1921 aged 51 sui. No CBDB entry.